Spring for door-fasteners.



S. P. STEVENSON. SPRING FOR DOOR FASTENERS. APPLICATION mum 001..31'. 100s.

' 965,418 Patented July 26, 1910.

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SPRING FOR DOOR-FASTENERS.

Specification of Letters Patent.

Patented July 26, 1910.

Application filed October 31, 1906. Serial No. 341,371.

TooZZ whom it may concern:

Be it known that I, SAMUEL PRICE STEVENSON, of Chester, in the county of Delaware and State of Pennsylvania, have invented certain new and useful Improvements in Springs for Door-Fasteners, whereof the following is a specification, reference being had to the accompanying drawings.

My invention relates to latch fasteners of the type heretofore invented and patented by me in United States Letters Patent No. 633,536, dated September 19th, 1899, and especially adapted for use in fastening the doors of refrigerator compartments wherein a very firm and close fit and fastening of the door is required. In the construction of these fasteners it is important to have a strong and durable spring not affected by rusting due to moisture, or by wear, and capable of maintaining with the proper degree of firmness, the engagement of the latch with its keeper. For this purpose as shown in said patent, a strong fiat rectangular spring has hitherto been employed by me, arranged so as to constitute a lever of the first class with a fulcrum in the middle, a bearing point at the lower end, and a pressure point at the upper end. But I have experienced difiiculty owing to the tendency of such a spring, when rectangular in shape as shown in said patent, to eventually break or become permanently set at or near the center where it passes over the fulcrum point. This is because in a flat spring of uniform width the greatest strain is experienced at that point, so that the bending action takes place chiefly there, and my present invention relates to means for so shaping a spring adapted for this purpose, as to distribute the strain, and therefore the bending action, evenly along the whole length of the spring, thus preventing it from being bent. I thus have secured a spring having a much greater life than those heretofore used without increasing the length or thickness of the spring, and there fore without increasing the size of the casing provided for my device. -This is accomplished by tapering the edges of the spring toward its ends, with provision upon the lower end of an offset whereby the tapering is prevented from interfering with the proper support of the bearing end of the spring.

In order to secure the maximum effective length of spring in the minimum size of casmg, I find 1t deslrable to taper one end of the spring upon one side, and the other end upon the otherjside, so that the extreme length of the spring is a diagonal one.

In the drawings, Figure I, is a front elevation of my improved door fastener containing a spring embodying my present invention. Fig. II, is a section along the line II, II, in Fig. I. Fig. III, is a detail view of my improved sprin In explanation of the construction shown in the drawings, the door 1, abutting against the door casing 2, is provided with a fastener contained within a casing 3, secured to the door by means of screws 4. Extending through the enlarged portion 5, of this casing is the latch 6, provided with an exterior handle 7, operated as a lever from the outside of the door, to move the latch 6, to which it is attached. The inside of the easing is provided with a recess 8, which receives and holds firmly in place the lower or bearing end of the flat spring 9, the central portion of which rests against a ledge 10, forming a fulcrum for the spring action, while the upper end of the spring resists the under side of the enlarged portion 11, of the latch operating handle. The ledge 10, is formed upon a plate 12, secured within the casmg.

The peculiar shape of the spring 9, upon which my present invention depends is most clearly exhibited in Fig. III, where it will be noted that the central portion of the spring, where it bears against its fulcrum, is of the full width of the ordinary fiat spring hitherto employed by me. Toward the lower end 13, the spring is diminished in width or tapered, the diminution being effected altogether upon one side with provision of an offset 14, at the extreme end, the purpose of which will be hereafter explained. The upper end of the spring is similarly tapered, the diminution in width being effected entirely upon the opposite side from that which is narrowed to form the taper of the lower end. The offset 14, enables the base of the spring to be maintained of full width, so as to afford a firm engagement for its lower end with the recess 8, provided for it in the casing. This is important because the proper seating of the spring without the creation of sidewise or torsional strains can only be thus secured.

The taper of the spring toward its ends has the result of spreading the bending action evenly over the length of the spring thus distributing the strains which otherwise would occur chiefly along'the line of the fulcrum 10. This result is accomplished without weakening the power of the spring without enlarging the spring, and therefore within the limits of the usual sized casing, and without any other objectionable modification of the device. Inother Words, by cutting away certain specific portions of the flat spring heretofore employed by me, I have secured a much better and more lasting device, lengthening the life of the spring and avoiding the danger of permanent set.

Having thus described my invention, I claim 1. In a fastening device, a flat spring fulcrumed at its center and tapered toward either end, one end of the spring being fixedly seated and the other forming a point of resistance for the latch operating members.

2. In a spring controlled latch fastener, the combination of a casing provided with a seat; a fulcrum bridge; a fiat spring resting at its lower end in the seat, abutting midway against the fulcrum ledge, and with its upper and free end resisting the latch operating mechanism, said spring being SAMUEL PRICE STEVENSON.

WVitnesses:

J AMES H. BELL, E. L. FULLERTON. 

